Thanks. I'll start, and then my colleague, Dr. Charles Lin, may add, since he's even closer to the science than I am.
If you consider the issue of ozone depleting substances, when action was taken under the Montreal protocol, there were predictions that it would take quite a long time to see the ozone layer regain its health and start stabilizing. That's what our monitoring, I would say, is starting to see. Even ten years ago scientists were predicting it would be the middle of this century, 2050, before we would really see those kinds of improvements.
We continue to be interested and have scientists look at the role ozone plays in the overall health of the atmosphere, because this is important to other issues, such as climate change. The interactions and impact of ozone, and the ozone level just in the atmosphere generally, are important to us.
Charles, did you want to add something more?